OK, let's work through this together. We're starting with 153 and we're going to multiply it by 124, which means we add 153 to itself 124 times.
Step 1: 0 + 153 = 153
Step 2: 153 + 153 = 306
Step 3: 306 + 153 = 459
Step 4: 459 + 153 = 612
Step 5: 612 + 153 = 765
Step 6: 765 + 153 = 918
Step 7: 918 + 153 = 1071
Step 8: 1071 + 153 = 1224
Step 9: 1224 + 153 = 1377
Step 10: 1377 + 153 = 1530
Step 11: 1530 + 153 = 1683
Step 12: 1683 + 153 = 1836
Step 13: 1836 + 153 = 1989
Step 14: 1989 + 153 = 2142
Step 15: 2142 + 153 = 2295
Step 16: 2295 + 153 = 2448
Step 17: 2448 + 153 = 2601
Step 18: 2601 + 153 = 2754
Step 19: 2754 + 153 = 2907
Step 20: 2907 + 153 = 3060
Step 21: 3060 + 153 = 3213
Step 22: 3213 + 153 = 3366
Step 23: 3366 + 153 = 3519
Step 24: 3519 + 153 = 3672
Step 25: 3672 + 153 = 3825
Step 26: 3825 + 153 = 3978
Step 27: 3978 + 153 = 4131
Step 28: 4131 + 153 = 4284
Step 29: 4284 + 153 = 4437
Step 30: 4437 + 153 = 4590
Step 31: 4590 + 153 = 4743
Step 32: 4743 + 153 = 4896
Step 33: 4896 + 153 = 5049
Step 34: 5049 + 153 = 5202
Step 35: 5202 + 153 = 5355
Step 36: 5355 + 153 = 5508
Step 37: 5508 + 153 = 5661
Step 38: 5661 + 153 = 5814
Step 39: 5814 + 153 = 5967
Step 40: 5967 + 153 = 6120
Step 41: 6120 + 153 = 6273
Step 42: 6273 + 153 = 6426
Step 43: 6426 + 153 = 6579
Step 44: 6579 + 153 = 6732
Step 45: 6732 + 153 = 6885
Step 46: 6885 + 153 = 7038
Step 47: 7038 + 153 = 7191
Step 48: 7191 + 153 = 7344
Step 49: 7344 + 153 = 7497
Step 50: 7497 + 153 = 7650
Step 51: 7650 + 153 = 7803
Step 52: 7803 + 153 = 7956
Step 53: 7956 + 153 = 8109
Step 54: 8109 + 153 = 8262
Step 55: 8262 + 153 = 8415
Step 56: 8415 + 153 = 8568
Step 57: 8568 + 153 = 8721
Step 58: 8721 + 153 = 8874
Step 59: 8874 + 153 = 9027
Step 60: 9027 + 153 = 9180
Step 61: 9180 + 153 = 9333
Step 62: 9333 + 153 = 9486
Step 63: 9486 + 153 = 9639
Step 64: 9639 + 153 = 9792
Step 65: 9792 + 153 = 9945
Step 66: 9945 + 153 = 10098
Step 67: 10098 + 153 = 10251
Step 68: 10251 + 153 = 10404
Step 69: 10404 + 153 = 10557
Step 70: 10557 + 153 = 10710
Step 71: 10710 + 153 = 10863
Step 72: 10863 + 153 = 11016
Step 73: 11016 + 153 = 11169
Step 74: 11169 + 153 = 11322
Step 75: 11322 + 153 = 11475
Step 76: 11475 + 153 = 11628
Step 77: 11628 + 153 = 11781
Step 78: 11781 + 153 = 11934
Step 79: 11934 + 153 = 12087
Step 80: 12087 + 153 = 12240
Step 81: 12240 + 153 = 12393
Step 82: 12393 + 153 = 12546
Step 83: 12546 + 153 = 12699
Step 84: 12699 + 153 = 12852
Step 85: 12852 + 153 = 13005
Step 86: 13005 + 153 = 13158
Step 87: 13158 + 153 = 13311
Step 88: 13311 + 153 = 13464
Step 89: 13464 + 153 = 13617
Step 90: 13617 + 153 = 13770
Step 91: 13770 + 153 = 13923
Step 92: 13923 + 153 = 14076
Step 93: 14076 + 153 = 14229
Step 94: 14229 + 153 = 14382
Step 95: 14382 + 153 = 14535
Step 96: 14535 + 153 = 14688
Step 97: 14688 + 153 = 14841
Step 98: 14841 + 153 = 14994
Step 99: 14994 + 153 = 15147
Step 100: 15147 + 153 = 15300
Step 101: 15300 + 153 = 15453
Step 102: 15453 + 153 = 15606
Step 103: 15606 + 153 = 15759
Step 104: 15759 + 153 = 15912
Step 105: 15912 + 153 = 16065
Step 106: 16065 + 153 = 16218
Step 107: 16218 + 153 = 16371
Step 108: 16371 + 153 = 16524
Step 109: 16524 + 153 = 16677
Step 110: 16677 + 153 = 16830
Step 111: 16830 + 153 = 16983
Step 112: 16983 + 153 = 17136
Step 113: 17136 + 153 = 17289
Step 114: 17289 + 153 = 17442
Step 115: 17442 + 153 = 17595
Step 116: 17595 + 153 = 17748
Step 117: 17748 + 153 = 17901
Step 118: 17901 + 153 = 18054
Step 119: 18054 + 153 = 18207
Step 120: 18207 + 153 = 18360
Step 121: 18360 + 153 = 18513
Step 122: 18513 + 153 = 18666
Step 123: 18666 + 153 = 18819
Step 124: 18819 + 153 = 18972

So, 153*124 = 18972